Boost phase ICBM engagement using space-based interceptors: A comparison of guidance laws

Boost-phase intercept of a threat intercontinental ballistic missile (ICBM) is the first layer of a multi-layered missile defense strategy. Space-based interceptors possess certain kinematic advantages over ground-based interceptors in defeating an ICBM threat during boost phase. This paper compares the performance of various guidance laws that might be used by an exo-atmospheric kill vehicle (EKV) launched from orbit to intercept a ground-launched ICBM during boost phase. Proportional navigation guidance, bang-bang guidance and predictive guidance are all investigated using simulated missile and EKV trajectories. Performance parameters used in this study are miss distance, intercept time, launch envelope, and total control effort. The predictive guidance algorithm outperformed the other guidance algorithms in these simulations when using perfect knowledge of the threat kinematics, but it proved to be very sensitive to time-to-go errors.